Lubricating oil



Patented Apr. 26, 1938 UNITED STATES LUBRIOATING OIL No Drawing. Application June 22, 1934,

t Serial No. 731,991 I 16 Claims.

The present invention relates to an improved lubricating composition and more particularly to an oil for the lubrication of automotive engines and other purposes. The invention will be fully understood from the following description.

It has been known and appreciated-for some time that hydrocarbon oils could be improved in respect to their lubricating properties by the addition of relatively small amounts of materials which increase their oiliness. Various materials have been suggested but most of these have certain objections, for example, eltherthat they are excessively corrosive, increase the carbon forming tendency of the oil or have an excessive oxidation rate. In the present application, which is a continuation in part of an earlier case, Serial No. 687,311, filed August 29, 1933, are disclosed a class of substances which are satisfactory for the present purposes in a very high degree.

The addition agents disclosed in the presen case comprise the class of acetylated? hydroxy acid compounds, by. which is included the acids themselves, their esters'and glycerides. Most of the acids, esters and glycerides are not miscible with mineral oils before acetylation but after such treatment they become in most cases miscible in all proportions.

The word acetylation" as used in the present specification is intended to have a broader significance than the mere treatment with acetic acid 'or strictly acetylating materials but is intended to cover broadly the type of reaction whether the acid used be acetic or other low molecular weight acids, particularly those containing from 1 to 5 carbon atoms, among which formic, propionic, butyric and valeric may bementioned, although it would be understood that unsaturated acids may also be used.

The materials which may be acetylated, as indicated above, include the hydroxy acids, esters and glycerides. Themost important single substance is castor oil which is primarily the glyceryl ester of ricinoleic acid. Castor oil may be used as r such or it may be subjected to hydrogenation in order to saturate the double bond; Among the acids which maybe used maybe mentioned the saturated hydroxy acids such as sabinic, juniperic and cocceric, which are merely mentioned as examples,'but' also the corresponding acids of the 50 unsaturated or ricinoleic series, may also be used,

,aidic. the di-hydroxy or poly-hydroxy acids may also be or digestion at an elevated temperature, for ex- PATENT (01. 87-9) a such as ricinoleic itself, isoricinoleic and ricinel- It will be understood furthermore, that used in which one or more of the hydroxyl groups; are acetylated, Poly-basic acids can also be em- 5 'ployed. Besides castor oil theglyceryl esters of all of the various acids of the classes 'mentioned above may be employed, and not only the glyceryl butglycol and mono-basic esters are .alsocon- I esterified'with monoor poly-basic alcohols. 1 20 I The acetylation, as indicated before, refers not only to the treatment with, acetic acid or its equivalents but also to other low molecular weight acids. For some reasonfwhich is at present ob,-

scure the reaction products prepared by difierent acetylation methods are not equally good for present purposes. In general it has been .found that the products produced bythe acetylation with acid chlorides are more desirable than those "prepared'in any other manner. Oils containing relatively small amounts of a product prepared in this manner are capable of carrying heavierloads with less friction than similar compositions con.- taining the products preparedby acetylation with acid anhydrides or with the acids themselves. As stated above,vthe reason for this is not fully understood but the superiority ofthe products prepared byacetylation with the acidchlorides is I substantial that these products are. greatly pre-, ferred. I m The acetylation may be conducted with acetic anhydrides or other acidanhydrides. The prod not of this reaction is found to be quite erratic in its load carrying or oiliness behavior. In -a few instances the oily material has been very good but in most cases it is decidedly inferior to the. product produced by 4 acetylation with acetyl chloride. However, it has been found that aheat treatment ample, from 200C. to 400 C. which is well below j time} It is often suflicieutmerely to distill over 'to of the reaction product in order to stabilize and greatly improve the undistille'd frac-j tions. In manyinstancesthere isfasmali acidity developed during'the digestion step and before usefof the product the acid should be.removed,'=

for example" by neutralization or lesteriiicationv with a small amount of alcohol. The material producedby direct acetylation "with the organic acid, using sulphuric or some other strong dehydrating agent in titanium manner, is also decidedly inferior totheproduct produced in the preferred method usingtheacid chloride. The inferiority shows itself as indicated above, in lowerload bearing capacity and a greater friction. 'I'hismaterialcahhlsobe V considerably improvedby the heat treatment outlined inthe previous paragraph.

The glyceryl esters ofihydroxy acidsgparticu larlycastoroil, are'thepreferred' raw materials for this process, and ashas been indicated before,

the preferred method i'spth'e 'acetylation by means of an acid chloride whichjyields a product of high oilines's value giving low'frlction and 'whichfcan I be readily reproduced. j Ithas been"found" th'at this product can be somewhat further improved by hydrogenation. which saturates the -ldouble bond." Such hydrogenation may be, carried out .with catalysts Tof-"the' type of nickeLffor others Iwhich= are well known, and at temperatures 'of the order gof fr omroom temperature to 250 C. or'highenwith'a hydrogen pressure adjusted" to theactivity of the catalyst'so as'to effect a satura-' tion ofthe unsaturated bonds. The heattreat ment mentioned above is not ordinarily necessary with the product "produced by means of-abetjl chloride or other iacid chloride, but when, the

product isproduced by'the other methods'merf tioned abovesuch heat treatment is highly desirable andmay be accomplished simultaneously fwiththe hydrogenationg j V ,j The amount of the'acetylated compoendsto be used depends to someextent on'the particular material :used', bllil inf general only relatively small'amounts are required, for example, as'littlej increase'the oiliness of a hydrocarbon lubricant} but usually "from 2, to'3 'or up to'5 or 6% may be desired. The hydrOgenation treatment improves not onlyf thelubricating value of the compounds but also increases their stabilitytocarbon deposition,and permits a somewhat larger amount to, be'us'ed without excessive formation of carboni f' T 'It' has' been found that' the addition of these oiliness compoundsordinarily increases the oxidation-rate er the lubricating oil employed. If the amount used does not exceed 5%, howeverjthe' oxidation rate-lis not asumciently increased .to be objectionable in ordinary gcases, but if larger amounts are usedthis maybe objectionable. In

any case the oxidation rate may; be corrected by r the addition of oxidation inhibitors which form a large class of known'cornpounds. Among these may be generally mentionedhydroxy' or aminov aromatics such asfthe naphthol and naphthyl amines; also thio phenolic 'aromatics'such asjthe thio-naphthols, organic polysulphides, thio ethers and til-sulphides, especially those containing aro- 'manner.

' maximumefriction of l5;v

an s v p matic groupaiand also metallo organic cornpounds. 0! these latter the lead, tin, mercury and bismuth aryl compounds 'are'the most desirable although alkyl compoundsiare; also useful. I Thefollowing examples-are produced to illustrate the propertiesof' the present compounds .and the eilectof the method, of production: i

(l) A sample of castor 'oil was acetylated by treatment with'acetyl chloride in the well-known Two percent of the product was. then addedto a highly refined petroleum lubricating oil Each weightxamounts to 1000 pounds per square 3 inch load and the friction is givenin pound'feet.

S. A. E. grade 20. This compounded oil and a blanksample which contained'noneof the acetylated castor, oil were then subjectedto a test on "the Mougey machine which has been described in National Petroleum News Vol.23, #45. In these. tests a steel pin and an aluminum bushing were; used with the following results:

Weight Final carried friction on; 17 riuun' S'ame' containing 2% aoetylated castor oil (acetylchloride) 24 (2);A product produced according to. the

method of Example 1 was carefully hydrogenated using a nickel catalyst, a'pressure of one atmosphere, and'a temperature of- 25C; Two percent of this material-was added tothe same 011 used i irr-Example-l and on the Mougey machine the compound. carried the. full (3) Six: samples of acetylat'edscastor" oil were acetylated using acetic anhydride. Ineach case the oil was prepared in the same manner and with the same care. Two percent of each of the com- P unds were themadded to" the same oil and were subjected to the Mougey test with'the following results. One sample =was"excellentand carried the full 25 .weightswith a. final friction of. 17. Two-samples were fair, carrying full 25 weights with a friction ranging from 32"to 35.- Three samples were quiteinferior, causing afailure at from 23120 25 "weights with undesirably high friQtiOnalvaIues i f f d 1 "(4) One of the"poor" samples ofthe'a'cetylated mixture used 'in'the previousexajmple was care- 2 5- weights :With: a

fully distilled, taking off approximately 15%'.

This product carried th ningzs weights with a final friction of '17,

(5) Four samples of castor oil wereacetyla'ted using a mixture of acetic andQsulphuric acid. When used in the oil in proportionof 2% these.

sans les carried from 24 to 25 weights "with frictions from 60 to 95. v subjecting the above sampics to heat treatment at a temperatureof 300 to 340 C. for-% hour irnproved'the qualityjofthe agents so that" on the average they were able to carry 25 weights with-a final friction of 10 to 17.

(6) A sample of castor oil was carefully hydrogenated and afterwards acetylated using a mix ture of sulphuric andac'etic acids. I When used in 'proportioniof about 2% iticarried the full ,25'

weights on the Mou g ey'machine with afinal fric-f tionof37. I

e 7) Two new automobiles, one a Ford and the second a Chevrolet, were run in{ on an oil containing 2%, of the acetylatedcastor oil prepared by theacetyl chloride method. These cars were run for 1100 and .1600 miles at anaverage speed of 35 to miles per hour, and atthe end of the ref period were found to be in excellent condition.

(8) Two percent and 5% respectively of acetylated castor oil were added to a well refined lubricating oil S. A. E. 20. The original blank and the two blended samples were then subjected to Sligh and oxidation tests with the following results:

Sligh 24-hour Oxidation rate Blank sample. 19. 1, 16. 6 226 Same plus 2% acatylated castor oil 17.4 269 Same plus 5% acetyleted castor oil 16.8 343 The Sligh test was conducted according to the ordinary or standard procedure with the excepfrom about 200 to about 15 c. c. of oxygen ab sorbed per 10 c. c. of oil per 15 minutes.

The present invention is not to be limited to any particular oiliness compound known to any particular method of acetylation but only to the following claims in which it is desired to claim all novelty inherent in the invention.

We claim:

1. Lubricating composition comprising a viscous hydrocarbonoil containing from to 5% of a product obtained by esterifying at least part of the OH groups of a hydroxy acid compound of a long chain fatty acid with a low molecular weight ester-forming aliphatic reagent containing the group 0 and selected from the group consisting of acids, anhydrldes and acid halides.

2. A composition according to claim 1 in which the esterified product is prepared by the action of an acid halide on a hydroxy acid compound.

3. A composition according to claim 1 in which the esterified product is prepared by the action of an acid chloride on a hydroxy acid compound.

4. A composition of matter according to claim 1 in which the esterified product is produced by the action of an acid chloride on castor oil.

5. Composition of matter according to claim 1 in which the esterified product is produced by the action of an acid chloride on castor oil and the final product subjected to hydrogenation.

6. Composition according to claim 1 in which the esterified product is prepared bythe action of an acid anhydride on the hydroxy acid compound.

7. Composition according to claim 1 in which the esterified productis prepared bythe action of acetic anhydride on a. hydroxy acid compound,

and this product issubjected to heat treatment at an elevated temperature whereby its lubricating properties are enhanced.

8. Composition accordingto' claim 1 in which.

the esterified product is prepared bythe a'ction of an acid anhydride on castor oil, and the product is subjected to heat treatment to enhance its lubricating qualities.

9. Composition according to claim 1 ini'which the esterified product is prepared by the action of acetic anhydride on castor oil and the product i is then subjected to hydrogenation.

10. Composition according to claim 1 in which the esterified product is produced byQthe action of an organic acid on the hydroxy acid compound in the presence of a dehydrating agent.

11. Composition according to claim 1 in which the esterified product is prepared by the action of an organic acid with from 1 to 5, carbon atoms on the hydroxy acid compound in the, presence of sulphuric acid, and the product further sub jected to heat treatment whereby its lubricating qualities are enhanced.

12. Composition according to claim 1 in which the esterified product is prepared by the action of an organic acid with from 1 to5 carbon atoms on the hydroxy acid compound in the presence of castor oil, and the product further subjected to hydrogenation whereby its lubricating qualities are improved. y

13. Composition according to claim 1 in which the esterified product is subjected to heat treatv ment at elevated temperature whereby its lubricating properties are enhanced.

14. Composition according to claim 1 inwhich the esterified product is prepared by the action of the said acid halide on the said hydroxy acid compound and the esterified product is subjected to hydrogenation.

15. Composition according to claim lin which the esterified product is prepared by the action of the said organic acid on the said hydroxy acid compound and the esterified product is subjected to heat treatment whereby its lubricating quail ties are enhanced.

16. Lubricating oil composition comprising a viscous hydrocarbon oil containing a small proportion of an ester having the formula,

in said formula represents the alkoxy group of a. hydroxy acid compound, having at least one OH group, of a long-chain fattyacid compound, R 

